As it is well known, open food stuffs deteriorate in a refrigerator. In spite of the fact that the cold temperature slows down bacterial growth. This decay is primarily based on two factors. The first is low or high humidity, which causes foods to dehydrate (low humidity) or have mold growth (high humidity). The second problem is the oxygen in the environment, which leads to oxidation of the foods.
The first problem is dealt with the conventional refrigerator crisper which (theoretically) maintains an optimal humidity in the crisper drawer that assists with the problem of dehydration and mold formation. However, the oxygen concentration in that drawer is essentially equal to that of room air and therefore the oxidation is not retarded. The oxidation of the food, which is the same chemical reaction as occurs with rust often leads to a browning color just like rust. This is seen most rapidly on cut fruits and vegetables such as lettuce cut in half or a sliced apple.
Burg (U.S. Pat. No. 4,061,483) teaches that low temperature, low pressure storage of food. Spencer (U.S. Pat. No. 6,113,962) teaches a process of packaging meat in noble gases. Graf (U.S. Pat. No. 5,284,871) teaches the placement of an oxygen scavenging composition in a package with food. Both Spencer and Graf deal with the package that the food is sold in. Hosaka (U.S. Pat. No. 4,754,611) teaches a refrigerator with carbon dioxide concentration. Bishop (U.S. Pat. No. 5,417,080) teaches a crisper with a mist sprayer. Kronenberger (U.S. Pat. No. 4,013,434) teaches a crisper with moveable vents for the adjustment of the humidity level. Bishop (U.S. Pat. No. 5,303,563) also teaches a vegetable crisper sprayer as done in Bishop (U.S. Pat. No. 4,860,555).
The use of controlled atmospheres for storage of fruits and vegetables is known for professional food processing facilities. For example Storage Control Systems, Inc. distributes fruit and vegetable storage system, which control the levels of carbon dioxide, nitrogen, humidity, and ethylene gases. They are located at www.storagecontrol.com. BOC Gases Division located at www.boc.com manufactures large systems that control carbon dioxide and nitrogen levels as well as the temperatures for the freezing of vegetables. In spite of the fact that the obvious benefit of controlled atmosphere for the storage of foods in refrigerators as shown by the uses in industry, no practical consumer unit has been taught in a scientific or patent literature to the best of the knowledge of the inventors.